A personal health monitor provides a user with the ability to monitor his overall health and fitness by enabling the user to monitor heart rate and/or other biometric information during exercise, athletic training, rest, daily life activities, physical therapy, etc. Such devices are becoming increasingly popular as they become smaller and more portable.
In addition to providing biometric information such as heart rate and breathing rate, a personal health monitor may also provide physical activity information, e.g., duration, distance, cadence, etc. As with the sensing or measurement of many parameters, however, the accurate determination of such information may be compromised by noise.
A user's cadence enables the user to monitor his current performance relative to his personal goals, and therefore represents a particularly useful physical activity parameter. As used herein, a cadence represents the number of repetitions per minute of some physical activity. For example, when the user is moving on foot, the cadence represents the number of foot repetitions or steps per minute. When the user is moving on wheels, the cadence represents the number of cycle repetitions (e.g., crank or pedal revolutions) per minute.
Conventional devices may monitor the cycling cadence, for example, using a cyclocomputer. A sensor system mounted to the crank arm and frame of the bicycle counts the number of pedal rotations per minute to determine the cycling cadence. While such devices are useful and reasonably accurate, they are cumbersome and cannot easily be used with multiple bicycles. Further, such devices cannot provide an accurate estimate of the number of steps per minute taken, e.g., by a runner. Further still, such devices generally do not provide additional performance information, e.g., calories burned, at least not with a desired degree of accuracy.
In addition, there is an increased desire for everyday users to have easy access to information regarding their exercise routine and/or the results of their exercise routine, regardless of the exercise conditions or circumstances. For example, the speed of a runner jogging through a neighborhood may easily be determined by using a Global Positioning System (GPS). When the user jogs on a treadmill, however, GPS is useless. In another example, it may be desired to determine a user's maximum oxygen consumption/uptake/aerobic capacity (VO2max) without subjecting the user to costly and time consuming tests in a laboratory set up for just such testing.
Thus, there remains a need for more portable devices wearable by a user and capable of accurately measuring and/or estimating biometric and/or physical activity parameters (e.g., heart rate and/or speed), and any associated physiological assessment parameters (e.g., VO2max), in a wide variety of scenarios.